关于紫棕土的性状及其分类命名商榷

本文报导了作者在全国第二次土壤普查中于江西省广丰等县查到了一种由玄武岩风化物发育的土壤,介绍了这种土壤的成土条件、形态特征和基本属性(剖面各层颗粒组成、养分状况、pH值和代换性能、粘粒化学组成、腐殖质组成及粘土矿物组成等)都与红壤显著不同,认为应在分类中单独分出。就此,作者提出这种土壤的分类命名商榷,拟命名为“紫棕土”。

DISCUSSION ON THE PROPERTIES AMD CLASSIFICATION OF ZIZONGTU(FURPLE-BROWN SOIL)

Soils derived from basaltic parent material in subtropical area have always been classified into red earth series. Results obtained in the SECOND SOIL GENERAL SURVEY indicated that soils from basaltic parent material differed greatly from red earth both in morphological characters and in geneeral properties. These soils should be classified seperately as an independent item.These soils, named "zlzongtu" or "purple brown soil' , have theflowing properies:1. Profile color is light brown to purple brown, color value is 5YR (4-5)/(2-4); transition of horizon is indistinct; texture is loam to heavy loam, physical clay ( <0.01mm ) content is 37-45%, clay horizon is indistinct.2. No desilicfication and allitization, with a silica-alumina ratio being above 3.2, a silica-scsquioxide ratio above 2.4, a ferrallitic-alimina ratio above 2.5, a higher degree of active-Fe 0.23-0.29, a lower degree of free-Fe 40%.3. Higher cation exchangeable capacity being 24-35m. e. /100g soil, base saturation 70-98%, lower exchangeable-Al, PH 5.3-6.2.4. Especially high phosphorus content, most are 0.2-0.3%,the highest can be 0.5-0.6%.5. The soils clay minerals companied by a little montmorillonite and quartzite are dominated by poorly crystalline kaolinite, by the mixtural mineral layers of kaolllinite-montmorillonite and by some hydromicas.